Association of blood-cell-based inflammatory markers with gut microbiota and cancer incidence in the Rotterdam Study

Background: Gut microbiota play a crucial role in defining the immune response. The immune response – gut microbiota interaction is implicated in various human diseases including cancer. Identifying the link between gut microbiota and systemic inflammatory markers, and their association with cancer, will be important to our understanding of cancer etiology. Results The current study was performed on 8,090 participants from the population-based Rotterdam Study. We found a significant association (false discovery rate [FDR] ≤ 0.05) between three gut-microbial taxa, namely the family Streptococcaceae , genus Streptococcus , and the order Lactobacillales with lymphocytes. In addition, we identified 95 gut-microbial taxa associated with inflammatory markers ( P-value  < 0.05). Analyzing the cancer data, we observed a significant association between higher SII levels at baseline (HR: 1.65 [95% CI; 1.10–2.46, P -value  ≤ 0.05]) and the higher count of lymphocytes (HR: 1.38 [95% CI; 1.15–1.65, P-value  ≤ 0.05]) and granulocytes (HR: 1.69 [95% CI; 1.40–2.03, P -value  ≤ 0.05]) with increased risk of lung cancer after adjusting for age, sex, body mass index (BMI), and study cohort. This association was lost for SII and lymphocytes after additional adjustment for smoking (SII = HR:1.46 [95%CI; 0.96–2.22, P -value  = 0.07] and lymphocytes = HR: 1.19 [95%CI; 0.97–1.46, P -value  = 0.08]). In the stratified analysis, higher count of lymphocytes and granulocytes at baseline were associated with an increased risk of lung cancer in smokers after adjusting for age, sex, BMI, and study cohort (HR: 1.33 [95%CI; 1.09–1.62, P-value  ≤ 0.05] and HR: 1.57 [95%CI; 1.28–1.92, P-value  ≤ 0.05], respectively). Conclusion Our study revealed a positive association between gut-microbiota, higher SII levels and higher count of lymphocytes and granulocytes with an increased risk of developing lung cancer.